example.java

java rc4 加密 rc4加密算法的一个实现

import java.security.InvalidKeyException;

/**
 * @author reikon (Thomas Dixon)
 * This file is released into public domain. (no license)
 */
public class Example {
    
private static final char[] HEX_DIGITS = {
    '0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f'
};
    
	/**
	 * @param args
	 */
	public static void main(String[] args) {
        // Key we'll use to encrypt
        byte[] testKey1 = {
            (byte) 0x01, (byte) 0x23, (byte) 0x45, (byte) 0x67, 
            (byte) 0x89, (byte) 0xab, (byte) 0xcd, (byte) 0xef
        };
        
        // Data we'll encrypt
        byte[] testIn1 = {
            (byte) 0x01, (byte) 0x23, (byte) 0x45, (byte) 0x67, 
            (byte) 0x89, (byte) 0xab, (byte) 0xcd, (byte) 0xef
        };
        
        RC4 rc4 = new RC4();
        
        try {
            rc4.engineInit(testKey1);
        } catch (InvalidKeyException ike) {
            // handle errors with the key here
            System.err.println(ike);
        }
        
        // arguments are (byte[] in data, int offset)
        String result = toString(rc4.engineCrypt(testIn1,0));
        
        // print result which is a hex string
        System.out.println(result);
        
        // For this exmaple, which is a test vector:
        //
        // Key   : 0123456789abcdef
        // Input : 0123456789abcdef
        // Output: 75b7878099e0c596
        
	} // main

    private static String toString(byte[] ba) {
        return toString(ba, 0, ba.length);
    }

    private static String toString(byte[] ba, int o00set, int length) {
        char[] buf = new char[length * 2];
        for (int i = 0, j = 0, k; i < length; i++) {
            k = ba[o00set++];
            buf[j++] = HEX_DIGITS[(k >>> 4) & 0x0F];
            buf[j++] = HEX_DIGITS[ k        & 0x0F];
        }
        return new String(buf);
    }    
}